While most air purifiers need at least a few hours of operating time to make any noticeable difference, 420 Purifier will provide satisfactory results even if it is used only while smoking. For extra efficiency, it can be left running for a short time after smoking. In case of daily use, clean the front part of the device – the aluminium grate that is intended for air intake with a vacuum cleaner once a month. This prevents the collection of excessive amounts of dust and debris on the grate, which would reduce the efficiency of the device. Approximate lifespan of activated carbon in 420 Purifier is 2 years, if the device is used on a daily basis, or longer if it is not. After the activated carbon is spent, the user can cheaply and easily change it (link).